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P 2 ‐purinoceptors regulate surfactant secretion from rat isolated alveolar Type II cells
Author(s) -
Rice Ward R.,
Singleton Fannie M.
Publication year - 1986
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1986.tb11148.x
Subject(s) - secretion , secretagogue , adenosine , purinergic receptor , chemistry , medicine , endocrinology , pulmonary surfactant , purine , gtp' , propranolol , antagonist , biology , biochemistry , receptor , enzyme
1 Rat isolated alveolar Type II cells were utilized to examine the effect of purine and pyrimidine analogues on secretion of pulmonary surfactant. 2 ATP potently stimulated [ 3 H]‐phosphatidylcholine ([ 3 H]‐PC) secretion in a time‐ and dose‐dependent manner. The effect of ATP was noted by one hour of exposure and persisted for three hours. The EC 50 (concentration producing 1/2 the maximal response) for ATP‐induced [ 3 H]‐PC secretion was 100 nM. 3 ADP was also a potent secretagogue for surfactant secretion, but AMP and adenosine had no significant effect on surfactant secretion at concentrations < 250 μM. The EC 50 for ADP‐induced [ 3 H]‐PC secretion was 250 nM. 4 Other purine and pyrimidine nucleotides (ITP, GTP, CTP, TTP) were examined for their effect on [ 3 H]‐PC secretion. All purine and pyrimidine triphosphates examined significantly augmented [ 3 H]‐PC secretion, but were much less potent than ATP. The EC 50 s were ITP = 10 μM; GTP = 100 μM; CTP = 250 μM; TTP = 100 μM. 5 Neither 8‐phenyltheophylline (10 μM, a P 1 ‐purinoceptor antagonist), propranolol (100 μM, a β‐adrenoceptor antagonist), nor indomethacin (10 μM, a prostaglandin synthetase inhibitor) inhibited ATP‐induced [ 3 H]‐PC secretion from isolated Type II cells. 6 These data provide evidence for regulation of surfactant secretion from alveolar Type II cells by a P 2 ‐purinoceptor.